Koisuru Kimochi (The Feeling of Love)
by Hazerushi
Summary: Killua somehow felt a different kind of feeling by the time he would get close to his brother Illumi when he reached the age of twelve. His heart beats fast always and he always feels like running away. What kind of feeling could it possibly be? Is it...a feeling of love? Pairs: KilluaxIllumi R&R
1. The new brother

"Hurry, hurry! Call a doctor, her water bag is bursting."

"Yes, sir."

That's what Illumi heard when he'd just arrived at the house. Everyone was panicking and his father Silva was ordering the butlers to do something about Kikyou, Illumi's mother. He didn't really know why everyone's in a rush, ever since he entered the mansion; everything looks like they're in chaos or something.

"Father, what's going on?" Illumi asked Silva.

"Your mother's about to give birth for your second brother." Silva explained. "Hurry up! Where's the doctor?" Silva yelled on the butler that was making the call.

"He- He's coming, sir. Just wait for a little while."

Silva went upstairs to check on his wife. Kikyou's been panting and a little stressed because she's about to give birth. Silva was trying his best to calm her down and Illumi was just staring at his mother and he was also told to stay out from this.

"Silva!"

"Calm down, Kikyou. The doctor will arrive here soon."

* * *

It took a little while for Kikyou to let her baby out but at last they made it. They were happy for the little child, crying on his mother's arms. Illumi was standing beside the bed with his mother on it and he stared at the little baby. He was glad that his new little brother was born but you couldn't see the gladness he had on his face because he's always showing such emotionless face.

"Illumi, meet your new brother." Kikyou smiled as she handed the baby on Illumi's arms.

Illumi held the baby and he saw his little brother sleeping on his arms.

"Kikyou, what name shall we call to our little child?" Silva asked.

"Hmm...I don't know. Let me think,"

"Killua," Illumi said.

"Yes? What is it, Illumi?" Kikyou said.

"His name will be Killua."

"Alright then, he'll be our little Killu." Kikyou grabbed her baby and looked at his sleeping face then he leaned down to her baby and kissed his forehead.

* * *

After 1 year, Killua finally turned 1 year old so they wanted to celebrate his birthday and his parents were the ones handling everything for his birthday. Kikyou became pregnant again and she'll bear another child after nine months. Illumi had fun playing with Killua and he's the one who takes care of him every day because he really likes Killua. Whenever he's on a mission, of course some of the butlers were taking care of him but actually Illumi's always excited to go home because he likes to play with Killua.

Right now, Illumi was on his mission because he'll have to assassinate someone. He liked to postpone his mission so that he could be able to celebrate Killua's birthday, but his parents were telling him not to worry about Killua. He had no other choices because ever since he was trained to become an assassin, he promised that he'll do whatever it takes to make the family proud of him. So, there he goes already, still trying to hide somewhere for a perfect timing to kill his own target.

This is quite hard because even when he's hiding his presence, his target could somehow feel like there's someone following her because she keeps looking back. Illumi's target was a teenager girl and she looks so innocent and nervous. For Illumi, even if that person he should kill is innocent or maybe didn't do anything, he shows no mercy for anyone, he just kills them directly because that's what the family trained him for. Illumi followed the girl silently and the girl kept walking forward. Illumi took out the needles from his pocket then he immediately threw it at the girl.

The girl dodged the needles quickly then Illumi showed himself at the girl.

"I knew there was someone following me." The girl spoke.

Illumi quickly dashed to the girl and he was about to thrust her with his hand but she ran quickly and Illumi didn't had the chance to hit her even once. The girl took her gun as her weapon then she started shooting at Illumi. Illumi dodged the bullets then he jumped at the girl and quickly threw needles at her. The girl hadn't dodged that so she collapsed on the ground then Illumi took the gun and shot her so many times until she's finally dead.

Illumi still had another mission and it's starting to get darker already. He actually hoped that he could still go home to celebrate his brother's birthday but now's not the time for him to think about it because he should hurry and search for his next target.

* * *

After he already completed his mission and killed five targets, it's already time for him to go home he was walking, he saw a small gift store then he thought about something. When he entered the store, he saw different kinds of things as gifts for someone.

"Good evening, sir." A woman greeted him.

Illumi didn't reply but he kept looking for something as a gift for his little brother. He saw a bear stuffed toy then he walked closer to it and stared at it for a little while.

"Have you picked something you liked, sir?" The woman smirked.

"How much is this?" Illumi asked, pointing at the stuffed toy.

"Umm... That'll be 1000 jenny, sir."

"Alright, I'll buy this one."

After Illumi paid for the stuffed toy, he wrapped it on a gift wrapper then he rode on a bus for him to go home already. His mission was on a far place so it'll probably take hours for him to reach his home.

He got home after 3 hours and the time was already 3:00 in the morning. When he entered the house, he saw inside his room that the lights are still on. Killua was actually sleeping on Illumi's room but anyway, he could also hear his brother's cry. There was a butler named Goto who's trying to comfort the baby and calm him down but it's no use because Killua's been crying and he won't stop.

"What's going on?" Illumi said.

"Ah, Illumi-sama! You're finally home."

"Why is he crying?" Illumi asked.

"Well, he won't stop crying, I don't know why. He doesn't want to be fed and there's nothing on his diapers, but he's just crying." Goto explained. "Killua-sama, please stop crying."

"Waaahhhh!"

"That's alright, I'll handle him. You could go now, Goto."

"A- Are you sure you could handle him, Illumi-sama?" Goto questioned.

"Yes,"

"Understood, Illumi-sama."

As Goto walked out and closed the door, Illumi took his brother then he tried to keep him quiet.

"Killu, please stop crying." Illumi said. "Onii-chan is already here. Onii-chan bought you something for your birthday."

Killua stopped crying then he opened his eyes then his blue eyes stared at his big brother. Killua smiled as he saw his big brother then his little hands touched Illumi's face.

"Happy birthday, Killu. Look, here's what I got for your birthday."

Illumi showed him the stuffed toy then he gave it to his little brother.

After a little while when Illumi had let his little brother sleep, he placed him on his little bed and his brother was even hugging and cherishing his stuffed toy. Killua snored so cutely and he's even sucking his little thumb, then after that, Illumi switched off the lights and lied down on his bed then closed his eyes for him to sleep because he's really tired on his mission for the whole day.

* * *

So, I wrote a Killumi story. I really love that pair so much! It's been enjoyable to write something about those brothers.

Next, there'll be another chapter, so please review if you want me to continue!


	2. Mission with Illu-nii

A few years had passed, Killua grew up and he turned 7 years old. So ever since he was 5, he was already trained on how to kill someone already. The way that they train him is for real, his father would take him into a place where his target was then his father watches him on how to kill his target. His family was proud of him for being a really great assassin; Illumi was the one who's mostly proud of him.

Killua and Illumi were siblings that were really close together. Illumi likes Killua a lot and he's been the brother he really liked the most than any of his siblings. Ever since Killua was born, he's already the one who he likes to take care of. Right now, they're still close, yet there's someone who's more close to Killua and that would be Killua's younger sister. Both of them play together always and Illumi had no time for Killua because he always had a mission. Whenever Killua asked Illumi to play with him, Illumi always refuses that's why everything has changed lately. But it's not really like Killua wanted to avoid Illumi, he understands the situation of his brother and he's hoping that both of them could still have a chance to hang out.

Illumi just came home and he's already back from his mission. Ever since two days passed, Killua's been finding Illumi so when one of the butlers told Killua that Illumi's back, he got excited then he ran outside to see his brother. Illumi saw Killua running towards him then he embraced him.

"Illu-nii!" Killua said.

"Killu, how are you? Did you miss me?" Illumi asked.

"So much! Hontou ni aitakute, Illu-nii..." Killua feels so glad that his older brother is back because he never got the chance to embrace him like this for so long. "Ne Illu-nii, do you still have a mission?" Killua looked up at Illumi.

"Well...yes," Illumi answered.

"Is that so?" Killua looked down with a disappointed look on his face. "Then, I would like to go with you."

"What?"

"I like to go with Illu-nii. I missed those times when both of us were hanging out together, so I wanted to go with you."

"Killu, my mission is dangerous...I would agree for you to come to prove yourself that you could handle it, but you should ask father."

Behind them, they heard footsteps and when they turned back, they saw Silva.

"I agree, Illumi had five targets and they're just in one group so I would agree for Killua to come." Silva explained.

"Really? Thanks dad!" Killua said with a face of excitement.

"Well, if that's what you want, let's go Killu."

Killua followed Illumi as both of them went to the airship to go to their targets' place. Illumi was controlling the airship and Killua was watching the view outside and he was amazed by it. It will reach a few minutes for them to arrive because they're just riding the airship so it'll just be fast.

When they arrived, Killua was the first one who got off and Illumi followed. Killua was really excited to kill their targets so Illumi led him to the place because he knows the location of their targets.

"Killu, when you're following or searching for the target, you should walk or run silently." Illumi said.

"Is that so?" Killua tried walking silently then he did it but he's walking too slow when he walks silently because he's not used to walk fast silently.

"Like this, you do it fast." Illumi demonstrated it to him and he walked faster silently.

Killua tried running silently without watching his steps then he was glad because when he tried it, he did it. He moved his feet without making a sound.

"Illu-nii, I did it!" Killua smiled.

"Great job, Killu." Illumi patted his head. "Let's go."

When both of them arrived to the place, they saw that the group of their targets where tall and strong. For Illumi, he could handle them and Killua could handle them too because he fought strong guys like those when he was at the Heavens Arena in the age of six but the problem is that they have their weapons and Killua wasn't yet trained into dodging just fighting.

"Killu, come here."

Illumi carried Killua using his back then Killua held Illumi tightly just for his safety. They're going to fight together and he wanted to carry Killua because Illumi moves so fast that Killua might not be able to catch up. So Illumi ran silently and hid somewhere safe. Killua was a bit nervous because he didn't know what to do when they'll get caught. Illumi could tell from his expression that his younger brother's nervous so he's trying his best to calm him down.

"Illu-nii, be careful okay?" Killua said.

"I will, we can do this. Just trust me, Killu."

Illumi released Killua then they went inside their targets' hideout together. They saw that their targets' were discussing about something. Illumi told Killua that they'll separate and Illumi will be the first to kill three targets and Killua will kill two targets. Illumi jumped from somewhere above then he threw his needles. Two of his targets got hit on the head then they became unconscious. Killua ran silently then he thrust one of his targets with his sharp nails. After that Killua killed just one target, someone suddenly grabbed him then his mouth was covered so that he won't be able to scream. Illumi saw that two of their targets escaped and one of them took Killua.

"Illu-nii!" Killua yelled as he uncovered the hands from his mouth.

"Shut up, kid."

"Your brother cannot save you anymore."

As the two men were running, they suddenly saw Illumi jumped in front of them.

"Let him go," Illumi said.

"Really?" The man took out his gun then he pointed it at Killua. "Then what if I kill this kid right now?"

"Let him go, don't make me repeat again or you will die."

The man tightened his grip on Killua's neck and he was pissed off.

"What if I won't?"

Illumi suddenly disappeared from their sights then he chopped off their heads. Killua was released then he coughed and panted. Illumi came to him just to see if his brother's alright.

"Killu, are you alright?" Illumi asked.

"Illu-nii!" Killua hugged Illumi then he sobbed. "I'm sorry...I'm sorry Illu-nii!"

"What's wrong, Killu?"

"I'm such a coward; I can't even escape from my target. I'm not good enough to be an assassin." Killua cried on his brother's shirt.

"That's not true. You did your best," Illumi stroked the hair of his brother. "You killed your target remember? Don't worry, you're already the greatest assassin for me."

"Really?"

"Yes, when you train some more you'll get even stronger than me, okay?"

"Okay, thanks Illu-nii." Killua wiped off his tears. "Illu-nii, can I ride on your back?"

"You must be tired Killu, come here." Illumi had let Killua climb on his back for him for ride on it.

Illumi walked along heading to the spot where the airship was bringing Killua with him. Killua was asleep on his back so when he got to the airship, he entered there then he placed Killua on the wide seat for him to lie down on it and to have some rest. This was his last mission for today so he should go home already and have some rest, at least he still have some time to probably do something in his house.

After a few minutes of travelling in the airship, they finally arrived home together. Killua was still tired so Illumi still carried him when they both went outside the airship then he walked inside the mansion and went inside Killua's own room then he placed him on his bed. As Silva walked inside Killua's room, he asked Illumi about Killua because he was worried for him if he could take another mission like that or not.

"Illumi, how's Killua?" Silva asked.

"He's fine, he's just tired." Illumi answered while he's looking at Killua.

"He's tired from killing his target? It must be hard for him. Then I will wait for him to her stronger until he could handle missions like that."

"No dad, he's totally fine; he killed two targets and I killed three because I wanted to see if he could really handle it. He's really a great assassin, you should give both of us missions like that again and if he could kill more targets than me, then he should be allowed to have a mission all alone by himself."

"Hmm...I guess you're right, train him some more Illumi."

"Yes, dad."

When Silva walked away and closed the door, Illumi saw Killua finally waking up. Killua rubbed his eyes then he sat up and stared at Illumi with his face still looking sleepy.

"Illu-nii," Killua said cutely. "Why did you lie to dad?"

"Eh?" Illumi was confused about what Killua said. "What do you mean, Killu?"

"Why did you tell dad that I made it successfully? You killed my other target for me, right? I only killed one, so why did you lie to him about it?" Killua looked down and looked up on his brother while he asked.

Illumi gave him a smile before he answered Killua's question then he walked closer to Killua then he patted his head.

"If I hadn't lied, dad will refuse your request for giving you a mission and if you want to come with me on my mission, the he might refuse. We can't let him know about it, okay?"

"Well even though you lied, thank you so much Illu-nii." Killua smiled. "You're the best brother ever." Killua hugged Illumi.

"Killu," Illumi wanted to ask him about something.

"Yeah?" Killua replied, still embracing Illumi.

"Nothing..." Illumi decided not to ask him about it because he's a bit embarrassed to ask him about it.

"I love you, Illu-nii." Killua said.

Illumi's eyes widened hearing what Killua said to him. It was the first time he heard those words from Killua. Well, they're siblings so there's nothing wrong if one of them says it. That was what Illumi wanted to say a while ago but Killua probably guessed what he wanted to ask so Killua just said it.

"I love you too, Killu." Illumi said as he hugged Killua tighter.


	3. Missed the chance

Illumi had just came home, back from his mission and he feels a little bit tired but he still had another mission later so he probably needed to rest even for just a while. Every time he's home, he always wanted to see Killua because he misses his favourite little brother all the time and it's been a while that both of them aren't assigned in a mission together. They've been having missions individually these days but Illumi wants to see Killua kill his target once again though he's just really proud of his brother. Killua always tells his servants to notify him if Illumi already came back home because he also wanted to see his big brother and he always feels happy when he'll see Illumi. Every time the butlers tell him that Illumi's home, he always came by running and heads to Illumi.

"Illu-nii!" Killua ran happily towards Illumi and embraced him. "Welcome home, Illu-nii!"

"Missed me much?" Illumi smiled a bit.

"So much, as always."

"Sorry for being away as always, Killu."

Killua shook his head then he looked up at Illumi and smiled.

"That's okay; it's your job to assassinate your targets."

"I was thinking," Illumi said. "Would you like to train with me?" Illumi asked him.

Killua was about to tell his big brother that he'd love to, but he was interrupted when his sister called his name and ran to him; so he went to his sister and asked her of what she needs.

"What is it, Alluka?" Killua asked her.

"Onii-chan, please play with me." Alluka requested.

By the time Alluka requested him to play with her, he had no other choices left. The only choice he had is to do what her sister requests because...there are quite some issues about her whenever she requests something.

"Killu?"

"I uh..." Killua still doubted about it. Even though he really wanted to go with his big brother and spend time with him, he still has to fulfill his sister's request. "Illu-nii, I'm sorry but Alluka still needs me. I guess I'll do it some other time," Killua smiled and rubbed the back of his head but on the inside, he feels bad about it.

"I see, well some other time then." Illumi said as he walked away.

Killua recalled about just earlier when Illumi was walking away and it looked like Illumi was being cold and upset, he didn't know. Illumi's always emotionless and he pulls out the same emotionless face all the time and Killua saw the same face earlier too, but according to his thoughts Illumi really liked to train with him even for just a while but he was refused and he got upset about it so Killua feels guilty about it. Or maybe he was just being paranoid...he doesn't understand it at all! He can't exactly tell what Illumi's thinking earlier because he never shows any emotions at all.

Killua's been standing there for a while already and Alluka was waiting for him to finish thinking but she can't wait to play with him so she just called Killua and hoped that he would respond.

"Onii-chan?" Alluka spoke.

Finally, Killua snapped out of thinking too much then he apologized to his sister and led her to the playing area. So they both started playing together, playing in the sand and Killua's helping Alluka build a sandcastle. Even though Killua's enjoying playing with Alluka, he's still worried about Illumi and wondering if Illumi's mad at him. He's already hesitating and thinking deeply and Alluka's been calling him but he wasn't focused to everything around him.

"Onii-chan!" Alluka spoke louder.

Killua got out of his thoughts then he smiled to Alluka.

"Ah, I'm so sorry Alluka."

"What's the problem?" Alluka shifted her position closer to Killua.

"I don't have any problems, I'm okay." Killua smiled as he denies.

Alluka folded her arms to her chest and made a pouty expression.

"I don't like big brothers that lie." Alluka said.

Killua sighed, since he didn't want to make his sister mad at him.

"It's about Illu-nii...I'm just worried if I'd let him get upset. He wants to spend some time with me and I do too, but it's just that I don't want you to be upset if I can't play with you, as your brother I want you to be happy." Killua explained to Alluka.

"I'm sorry, onii-chan. I shouldn't have got in your way, you always spend lots of your time with me and you haven't got the chance to spend time with Illumi-niichan because he's always away. He had his free time today and I managed to pull you away from him, I'm really sorry onii-chan, Nanika's sorry too." Alluka bowed down her head as she apologized.

Killua smiled and patted Alluka's head.

"You shouldn't be sorry, but thanks for being considerate about it."

"I would do anything to make onii-chan happy," Alluka smiled brightly.

"But, what about you? Will you be okay if I'll leave you here? I don't want you to be alone." Killua was worried about Alluka because he really needs to watch over her.

"Don't worry; I'll be playing with Kalluto-chan." Alluka smiled for Killua not to feel worried about her.

Killua ran along, heading inside the mansion and searched for his brother. When he went to Illumi's room and got inside, he saw nobody inside then he walked out of Illumi's room and searched for him somewhere around the house. He saw other servants walking by, so he ran to them to ask where Illumi was.

"Have you seen Illu-nii?" Killua asked.

"He already left, Killua-sama," One of the butlers answered.

"Left? To where?"

"He's having his mission today and I heard that he's going to a far place."

Killua's starting to panic and feel a bit nervous.

"When will he come back?"

The two servants looked at each other confused then they smiled nervously at Killua.

"We're very sorry Killua-sama, but we have no idea when Illumi-sama will return."

He immediately ran upstairs because he got no information about Illumi, so he headed to his parents' room because they probably know where his brother was and they're mostly the ones who're assigning the missions.

As Killua entered his parents' room, he can see both of his parents discussing something but then he suddenly asked something.

"Dad, mom, where's Illu-nii?"

Killua's parents were surprised yet worried because he looks tensed.

"He's already off to his mission, Killu." Kikyou, Killua's mother replied with a smile.

"I want to go with him," Killua insisted.

"Killu, what's with the sudden request? We can't allow you to go with your brother for now. His mission is very dangerous and if you go with him, you probably won't handle it and it will cause for Illumi to have trouble with his mission because of you," Kikyou explained worriedly.

"But, but, I really..."

Silva placed his hands on Killua's shoulders.

"Your mother is right, Killu. We're sorry but it's for the best," Silva said.

Killua looked down with a disappointed look on his face, feeling guilty because he wasn't able to tell his brother of what he wanted to say to him. Killua ran off from his parents' room then went inside his room, closed the door then he collapsed on his bed and covered his face with a pillow.

"Illu-nii...I'm sorry...I miss you so much..."

* * *

"Killu?"

Killua heard a familiar voice while he's asleep but he didn't mind and just continued to sleep.

"Killu?"

Killua heard the same voice mentioning his name and still he didn't respond.

Illumi was staring at Killua while he's sleeping and he's the one who's been calling out Killua's name. He kept trying to wake his little brother up but his little brother still wanted to sleep. He just watched Killua while he's sleeping and stopped disturbing him for a while because it is nice to look at Killua's cute sleeping face.

"Mm..."

Illumi heard Killua making a sound and also started shifting his position while sleeping.

"Illu-nii...I miss...you..."

Illumi saw Killua's tears flowing down from his eyes and he also kept mentioning Illumi's name. Illumi wiped the tears from Killua's eyes, and he stroked his hair.

"Don't cry Killu, onii-chan is here." Illumi smiled.

Killua finally stopped crying and he calmed down a bit. He's starting to open his eyes slowly then blinked. He sat up and his vision was a bit unclear so he rubbed both of his eyes and after that he's starting to see a clearer view.

"Illu-nii?" Killua said, looking at Illumi in disbelief.

"Killu, you're awake."

Killua stared at Illumi in a while, not saying anything but looking at him as if he couldn't believe that it's really Illumi. Is he seeing Illumi for real? Or he was still dreaming? He still doubts about it. But wasn't Illumi on his way to his mission? There's no way he'd return this early.

"Illu-nii..." Killua said in a calm tone and expression.

"What is it, Killu?" Illumi patted Killua's head.

_'Did Illu-nii just pat me? I can feel his warm hand on top of my head, so that means...'_

Killua's tears filled Killua's eyes until it flowed down to his cheeks. Illumi wondered what made his little brother cry and a confused look marked on his face. Killua grabbed Illumi's hand from his head and placed it near his chest then intertwined his fingers on Illumi's.

"Thank goodness..." Killua sobbed. "Thank goodness you're back Illu-nii!" Killua was really glad to see his big brother that he can't hold his tears because he's just so happy.

"Killu?"

"I'm sorry! I'm sorry that I ruined our chance to spend time together and train together. It's all my fault, I'm so sorry..." Killua cried while embracing Illumi.

"It's not your fault Killu, don't blame yourself." Illumi stroked Killua's soft silver hair. "We can still hang out together tomorrow." Illumi smiled.

Killua looked up at his brother with a confused look.

"But what about your mission..."

"It's my day off tomorrow. We can train and spend time together, would you like that?"

Killua smiled with his eyes closed and nodded.

* * *

Here's chapter three! Thanks for reading this chapter, please don't forget to review ^^

I'm sorry I haven't updated for a long time. Even though I started this chapter a long time ago, I wasn't able to finish because I ran out of ideas and I wasn't inspired to write. I know the chapters I wrote were short but I'll try to make it longer for the later chapters.

I want to thank those who followed and reviewed for my story! I appreciate it so much :)


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